\documentclass[a4paper, twoside]{article}
\usepackage[english]{babel} 

\usepackage[latin1]{inputenc}   % Encodage ISO-8859-1.
\usepackage{pgf}

\begin{document}

\begin{figure}[h]
\centering
{
\small
\input{test_out.pgf}
}
\caption{This is a test. Please note that it is perfectly normal that the PGF export does not include the text size and font attributes, since the idea is that the user might control those aspects via LaTeX commands.}
% \label{fig_test_out}
\end{figure}

\end{document}
